The NES changed the way sports games were made. Up until this point, sports games were very basic interpretations of the sport in question and had nothing else to them.
Baseball Stars was released by SNK in 1989. It was a port of the NEO GEO AES arcade title of the same name and totally revamped how sports games were from here on out.
While not based on any legitimate teams or even license, Baseball Stars offered more than just a baseball simulation. It now offered the chance for players to customise their own teams, alter player stats and even their salary. Even on field moves like running up the boundary walls to catch a home run were added.